Hydrogen peroxide nitriles, oxidation with

The nitro-substituted seleninic acid 103a was also found [531 to be an effective catalyst for the hydrogen peroxide mediated oxidative conversion of aromatic hydrazones 107 into nitriles 108 (Eq. 21). However, oxidation of hexanal dimethylhydrazone with this system gave only the parent aldehyde. 

Weak to moderate chemiluminescence has been reported from a large number of other Hquid-phase oxidation reactions (1,128,136). The Hst includes reactions of carbenes with oxygen (137), phenanthrene quinone with oxygen in alkaline ethanol (138), coumarin derivatives with hydrogen peroxide in acetic acid (139), nitriles with alkaline hydrogen peroxide (140), and reactions that produce electron-accepting radicals such as HO in the presence of carbonate ions (141). In the latter, exemplified by the reaction of h on(II) with H2O2 and KHCO, the carbonate radical anion is probably a key intermediate and may account for many observations of weak chemiluminescence in oxidation reactions. 

Incompatibility of the nitrile group with the oxidative work-up of the L-Selectride reduction using basic hydrogen peroxide Significant hydrolysis to the primary amide with concomitant exothermic activity and loss of product... 

A solid-phase synthesis of 3-substituted isoxazoles 31 in good yields and purities was achieved by 1,3-DC of polymer-supported vinyl selenide with in situ generated nitrile oxides treatment of intermediate isoxazolines 30 with an excess of hydrogen peroxide resulted in the release of isoxazoles 31 while the use of Mel/Nal led to 3-substituted 5-iodoisoxazolines... 

The oxidation of thioamides 63 with a wide variety of oxidizing agents is a well-employed method for the synthesis of 3,5-disubstituted-l,2,4-thiadiazoles 64 <1982AHC285>. However, this method is limited mainly to arylthioamides. The most common oxidizing agents tend to be halogens, hydrogen peroxide, dimethyl sulfoxide (DMSO), and nitrous acid. Yields from these reactions are variable and depend on the thioamide, oxidant, and conditions used (Equation 19). By-products such as nitriles and isothiocyanates are usually formed. 

More decisive evidence is provided by the interconvertibility of N-aryl-JV-arylamidinothioureas (28) and Hector s bases by oxidation-reduction.63, B4,67b The former compounds are accessible (as salts) (i) by the condensation of arylthioureas (24) with arylcyanamides (23),63 (ii) by the extrusion of sulfur from the recently described40,41 s-diaryldithioformamidine hydrobromidesB4a (22), (tit) by the oxidation of arylthioureas (24) with 0.5 moles of hydrogen peroxide in the presence of mineral acids,B4a and (iv) by the mild reduction of Hector s bases by hydrogen sulfide in acid media.B4a The first of these four reactions limitB the structure of the products to the three alternatives 25, 28, and 30. Of these, 25 is excluded by the non-identity of the product with authentic67 N-phenyl-i -phenylamidinothiourea (25 R = Ph). The monosulfide structure (30) is not reconciled as readily with the observedB4a hydrolytic fission of the products into diaryl-guanidines (29) and thiocyanic acid as is structure 28. Indeed, as in the case of thioamides and nitriles (see Section II, C, 1), the present condensation may involve the primary formation of an intermediate diimido-monosulfide (30) and its isomerization to 28. 

The most widely used and, presumably, the most chemoselective reagents for the epoxidation of nucleophilic C—C double bonds are the peroxycarboxylic acids (see Houben-Weyl, Vol. IV/ 1 a, p 184, Vol. Vl/3, p 385, Vol. E13/2, p 1258). Using chloroform as solvent, epoxidation rates are particularly high79. Reactive or acid/base sensitive epoxides can often be obtained with dimethyldioxirane (see Houben-Weyl, Vol. R13/2, p 1256 and references 15, 16, 87-90), peracid imides (see Houben-Weyl, Vol. IV/1 a, p 205, Vol. VI/3, p 401, Vol. E13/2, p 1276) (prepared in situ from nitriles and hydrogen peroxide), hydroperoxy acetals (see Houben-Weyl, Vol. El3/2, p 1253) or peroxycarbonic acid derivatives (see Houben-Weyl, Vol. IV/la, p 209 and references 17-19) as oxidants. For less reactive alkenes, potassium hydrogen persulfate is a readily available reagent for direct epoxidation20. 

Oxidation of the Schiff bases (19) made from the monoamide of DAMN (derived from DAMN by hydration of one of the nitrile functions) gives 4-cyanoimidazole-5-carboxamides (20) in good yields ( 70% or more) (Scheme 2.1.7). Such oxidations can be readily accomplished using hydrogen peroxide with a catalytic amount of sodium molybdate fSl]. 

Cyanopyrazine A -oxides have been prepared from a-amino nitriles and a-hydroxyimino carbonyl compounds as summarized in Section III. 1 (528-530, 532-534, 537, 540, 542). Oxidation of 2-cyanopyrazine with perhydrol gave 3-cyanopyrazine 1-oxide (575), 2-cyano-5-ethoxy-3,6-dimethylpyrazine with 30% hydrogen peroxide in acetic acid at 55° gave 2-cyano-5-ethoxy-3,6-dimethylpyrazine iV-oxide (288), and the oxidations of 2-amino-3-cyanopyrazine 1-oxide (538) and... 

D-Galactopyranosyl-D-arabinose was prepared from lactose oxime by dehydration with acetic anhydride and degradation of the resultant nitrile with sodium methoxide in chloroform. This galactosylarabinose has also been prepared by the oxidation of calcium lactobionate with hydrogen peroxide and a ferric salt (the Ruff degradation ). Under... 

MyV-Dimethylhydrazones of aldehydes react with hydrogen peroxide in the presence of catalytic amounts of MTO to give the corresponding nitriles in high yield [19]. The reaction commences with the oxidation of the Af,A -dimethyl-hydrazone and presumably proceeds through an intermediate which can undergo a Cope-type elimination to yield the nitrile (eq. (8)) [3, 19 b]. 

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